


Monthly Cycles

by IvyCpher



Category: Gravity Falls
Genre: Alpha Bill Cipher, Alpha/Beta/Omega Dynamics, Alpha/Omega, BillDip, Human Bill Cipher, Knotting, M/M, Mating Cycles/In Heat, Omega Dipper Pines
Language: English
Status: Completed
Published: 2017-06-07
Updated: 2017-06-07
Packaged: 2018-11-10 08:59:00
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 755
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11123988
Author URL: https://archiveofourown.org/users/IvyCpher/pseuds/IvyCpher
Summary: Bill waits for Dipper's heat to start so he can finally mate him.





	Monthly Cycles

Bill sighed in aggravation. Today was supposed to be that day his omega mate, Dipper, started his heat. Bill had not let Dipper leave the bedroom of their apartment all day. He stayed clinging to Dipper just waiting for him to start.

Bill already wanted to fuck the omega senseless, he was growing restless. “Pinetree,” He growled lowly. “You said you start today.”

“I-I do!” Dipper defended, turning away from Bill. “We go through this every month.” He mumbled. “It’s not like I get a letter in the mail telling me exactly what time I start.” Dipper had been feeling the affects of his pre-heat all day. He just wanted to nest, but that’s hard to do when your alpha won’t let you move.

Bill frowned and licked Dipper’s cheek. “This isn’t any easier for me.”

“I know.” Dipper shivered, Bill hadn’t scented him, but his saliva felt cool and nice on his warm skin. The omega nuzzled Bill, taking in his scent. “I would probably start sooner if you would let me nest.”

Bill reluctantly let go of Dipper. “Fine.” The alpha grumbled.

Since Dipper’s nest was always their bed, he had to remake it every month. “Can you go get me that one yellow sweater you always wear from the closet?” Dipper asked, arranging the bed’s blankets into a circle position.

“Yeah, yeah.” Bill got up and went to the closet. Dipper heard the noise of coathangers being shuffled around before a soft blob hit him in the face.

Growling softly, Dipper took the sweater and held it close. Then he took off his own shirt and put it on. “You could’ve just handed it to me.”

“I didn’t wanna.” Bill plopped down on the bed beside Dipper and wrapped his arms around him.

“Don’t mess up my nest.” Dipper mumbled, nuzzling up to Bill. He enjoyed the strong scent of the alpha, it made him feel comfortable.

“I won’t.” Bill mumbled back, nuzzling his face into the omega’s neck.

Bill’s hot breath on his neck made Dipper’s cheeks darken, he could feel himself starting to urge for the alpha. “B-Bill, I’m-.”

“I know.” Bill growled, his voice suddenly a in a deeper tone. He licked a long, slow stripe down Dipper’s neck before pulling away. The omega was all Bill had his mind on right now.

Dipper whined and held Bill close as he scented him. “Alpha.” The omega moaned. “Please.”

Bill growled as he started to nearly rip off Dipper’s pants. He had a clear enough mind to not rip his favorite sweater off the omega.

Dipper gasped at the feeling of the cool air on his hot flesh. Whimpering, he tried to hold Bill close as he removed his own pants.

Bill nipped at the omega’s neck while he kicked off his pants. He was already hard. “God, kid, you’re always so needy during your heats.” The alpha smirked, his enlarged fangs clearly visible.

“Y-You were just so clingy ten minutes ago.” Dipper wrapped his arms around Bill holding him close. He yelped out when he suddenly felt the alpha penetrate him.

“But am I clingy now?” Bill whispered in the omega’s ear.

Dipper clawed at the alpha’s back, moaning his name. “N-No! You’re not, alpha!” 

Bill’s fast, deep, thrusts made the bed creak and the headboard pound against the wall repeatedly. Bill would fill the omega to the hilt, but not anymore. Dipper wanted, no he needed to be knotted.

“A-Alpha please!” He moaned out. “Knot me!”

Bill howled and thrusted forcibly into the omega, finally knotting him.

Dipper felt Bill’s hot seman fill him and he came too.

They both panted for a minute before the fog that was covering their rational thinking was lifted. Bill hissed and brought one his hands up to rub his back. “You need to cut your nails, kid.”

“You know I can’t help it.” Dipper looked at his nails, they were claws like at the moment, but they would soon retract into his normal nails. “Sorry.” He muttered, cupping Bill’s face and kissing his nose.

“The pain isn’t that bad.” Bill smiled. “I like it.”

Laughing, Dipper nuzzled Bill. “Yeah, of course you do.” He sighed in content. “At least we mated in a good position this month, last time I was in heat we were stuck in the doggy-style position for twenty minutes.”

“I didn’t mind it, but yeah, it’s better to see your face.” Bill kissed Dipper’s forehead.

“My alpha.” Dipper muttered, wrapping his arms around Bill’s neck.

“My omega.”

**Author's Note:**

> I haven't done an ABO BillDip before, so I hope this is good. In all honestly, I prefer working on WillDip.


End file.
